JPS62145540A - Suspension spring of actuator of optical pickup device - Google Patents

Abstract

PURPOSE:To suppress the resonance due to a linear motion and the rotational motion of an objective lens by providing the first - the fourth spring materials and a viscoelastic substance. CONSTITUTION:To the rotational motion of the objective lens by the driving force in a focus direction, the first and the second spring members 1 and 2 of the suspension spring execute the extending and contracting motion like an accordion, the resonance frequency is decreased, and the viscoelastic sub stance 5 packed between these spring members absorbs the oscillation of the spring member. When the first and the second spring members 1 and 2 execute the extending and contracting motion, the third and the fourth spring members fixed only with one edge respectively are not extended and contracted, and therefore, between the first - the fourth spring members 1-4, the relative displacement occurs and the viscoelastic substance 5 effectively adsorbs the oscillation of these spring members.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a suspension spring that swingably supports an objective lens in an actuator of an optical pickup device used in a video disc player, a compact disc player, etc. [Summary of the invention] Both ends of the first and second spring members bent in a waveform are connected to the front and rear connecting portions connected to the objective lens and the actuator body, respectively, and the first and second spring members are connected to each other. Third and fourth spring members each having a base end connected to only one connection part and a tip extending beyond the center part are provided between them, and a viscoelastic body is filled between the first and second spring members. Alternatively, it is a suspension spring in which resonance is effectively suppressed by bonding a viscoelastic body backed by a single sheet across all of the first to fourth spring members. K. Prior Art Conventionally, in an actuator for controlling an optical pickup device so that a laser beam is correctly irradiated onto a signal recording track of a disk, the actuator is controlled by a suspension spring with two objective lenses provided on each side of the actuator. There is a well-known device that is swingably supported on the main body and that performs focus control and tracking control by driving a focus coil and a tracking coil fixed to the objective lens to move the objective lens parallel to the optical axis. It is being However, in such devices, the movement of the objective lens causes the suspension spring to resonate at a specific frequency, and when driving the objective lens, the driving force is applied to a position that is slightly away from the center of gravity. Therefore, there is a drawback that not only linear motion but also rotational motion occurs, and the suspension spring resonates due to this rotational motion at a frequency higher than the above-mentioned frequency. [Problems to be Solved by the Invention] The purpose of the present invention is to improve the drawbacks of the conventional device described above, and to provide a suspension gradient that suppresses resonance due to linear and rotational motion of an objective lens. . Means for Solving Problem K] In order to achieve the above object, the suspension spring of the present invention has front and rear connecting portions connected to the objective lens and actuator body, respectively, and both ends connected to the front and rear connecting portions, respectively. and first and second spring members connected to the rear connection part and bent in a wave shape, and provided between the first and second spring members, the proximal end of which is connected to the front connection part, and the distal end of the spring member bent from the center part. a third spring member that extends rearward; a fourth spring member that is provided between the first and second spring members, has a proximal end connected to the rear connecting portion, and a distal end that extends forward from the central portion;
Consisting of a viscoelastic body filled between the first J3 and the second spring member, or a viscoelastic body bonded across all of the first to fourth spring members and lined with one sheet. There is. [K effect] By doing this, the first and second spring members extend and contract like an accordion in response to the rotational movement caused by the driving force in the focus direction, lowering the resonance frequency, and reducing the resonance frequency due to the viscoelastic body. It increases the vibration damping effect, and also allows the first and second spring members to move at one end when they expand and contract.

[Since the third and fourth spring members to which the spring is fixed do not expand or contract, a relative displacement occurs between the first to fourth spring members, and this causes the viscoelastic body interposed between each spring member to Vibration is effectively absorbed. K Embodiment A first embodiment of the present invention will be described with reference to FIG. The eggplant pension spring includes the first to fourth IJ members 1 to 4.
, consists of a viscoelastic body 5 J3 filled between these spring members, a front (left side in the figure) and a rear connecting part 6.7 that support the spring members, and two upper and lower suspension springs (lower (not shown) are integrally formed and connected by claw portions 8.9 at the front and rear connecting portions 6, 7, respectively. The first and second spring members 1.2 have a wave-shaped bent shape, and both ends thereof are connected to the front and (nine-way) connecting portions 6.7, respectively. The spring member 3.4 has a substantially linear shape, and the base end of the third spring member is connected to the front connecting portion 6, and the distal end thereof is free to extend rearward from the center portion. Further, the base end of the fourth spring member (symmetrically with the third spring member 3) is connected to the rear connecting portion 7, and the tip thereof is freely extended forward from the center portion. A viscoelastic material 5 such as butyl rubber or silicone rubber is filled between the first and second spring members 1.2 by, for example, silk screen printing (for example, Japanese Patent Application No.
(Refer to No. 193089) It is adapted to absorb one sliding movement of the first to fourth spring members. The two upper and lower suspension springs that are integrally formed by etching are left as they are, and the front and rear connections 6.7 are adhesively fixed to the objective lens of the actuator and the actuator body, respectively (electrically). For separation), break off the front and rear claws 8.9 and separate into upper and lower parts. Next, the effect during operation will be explained. The first and second spring members of the suspension spring extend and contract like an accordion in response to the rotational movement of the objective lens due to the driving force in the focus direction, lowering the resonance frequency and filling the space between these spring members. The viscoelastic body absorbs the movement of the spring member. Furthermore, when the first and second spring members extend and contract, the third and fourth spring members, which have only one end fixed, do not extend or contract, so a relative displacement occurs between the first to fourth spring members. , the viscoelastic body effectively absorbs the movement of these spring members. FIG. 2 shows a second embodiment. The difference from the first embodiment is that instead of filling the space between the first and second spring members 1.2 with the viscoelastic body 5,
The dump sheet 10 straddles all of the fourth spring members.
This is the point where it is glued. The dump sheet 10 is a sheet 11 made of aluminum, plastic, etc., on which a viscoelastic body 5 is provided, and after the metal part of the suspension spring is completed, the dump sheet 10 is placed on one side of the metal part of the suspension spring. %' compared to the suspension spring of the first embodiment because it only needs to be glued.
M is extremely simple. [Effects of the Invention] As explained above, the eggplant suspension spring of the actuator of the optical pickup device described in claims 1 and 2 of this application has the following unique effects. It is something to play. (2) The first and second spring members bent in a waveform extend and contract like an accordion, thereby lowering the resonance frequency and effectively absorbing the vibrations by the viscoelastic body. ■When the first and second spring members make an expansion and contraction movement, -
Since the third and fourth spring members, of which only one is fixed, do not expand or contract, a relative displacement occurs between the first to fourth spring members, whereby an effective vibration absorption effect is performed by the viscoelastic body. ■Furthermore, the use of a viscoelastic material backed by a single sheet simplifies manufacturing.

[Brief explanation of drawings]

Fig. 1: Front view of the first embodiment of this invention Fig. 2:
...Front view of the second embodiment of this invention FIG. 3...(A) Front view J3 and (B) Right side view of the dump seat 1-4...First to fourth spring members 5...Viscoelastic body

Claims (2)

[Claims] (1) (A) Front and rear connection parts connected to the objective lens and actuator body, respectively; (B) First and second connection parts whose both ends are connected to the front and rear connection parts, respectively, and are bent in a waveform. (c) a third spring member provided between the first and second spring members, the base end of which connects to the front connection part and the distal end extending rearward from the central part; (d) the first spring member; and (e) a fourth spring member provided between the second spring member, whose base end is connected to the rear connecting part and whose tip extends forward from the center part; (e) between the first and second spring members; A suspension spring for an actuator of an optical pickup device, which is made of a filled viscoelastic material. (2) (a) Front and rear connecting parts connected to the objective lens and actuator body, respectively; (b) first and second connecting parts each having both ends connected to the front and rear connecting parts and bent in a waveform; (c) a third spring member provided between the first and second spring members, the base end of which connects to the front connection part and the distal end extending rearward from the central part; (d) the first spring member; and a fourth spring member which is provided between the second spring member and whose base end is connected to the rear connecting part and whose tip extends forward from the center part; (e) all of the first to fourth spring members; A suspension spring for an actuator of an optical pickup device, comprising a viscoelastic body which is bonded together and lined with a single sheet.